diff --git a/src/frostfs_testlib/steps/metrics.py b/src/frostfs_testlib/steps/metrics.py
index 29e49d4..c89e6d3 100644
--- a/src/frostfs_testlib/steps/metrics.py
+++ b/src/frostfs_testlib/steps/metrics.py
@@ -1,8 +1,8 @@
 import re
 
 from frostfs_testlib import reporter
-from frostfs_testlib.testing.test_control import wait_for_success
 from frostfs_testlib.storage.cluster import ClusterNode
+from frostfs_testlib.testing.test_control import wait_for_success
 
 
 @reporter.step("Check metrics result")
diff --git a/src/frostfs_testlib/storage/cluster.py b/src/frostfs_testlib/storage/cluster.py
index 9fcc4c9..b67e34d 100644
--- a/src/frostfs_testlib/storage/cluster.py
+++ b/src/frostfs_testlib/storage/cluster.py
@@ -11,10 +11,10 @@ from frostfs_testlib.storage import get_service_registry
 from frostfs_testlib.storage.configuration.interfaces import ServiceConfigurationYml
 from frostfs_testlib.storage.constants import ConfigAttributes
 from frostfs_testlib.storage.dataclasses.frostfs_services import HTTPGate, InnerRing, MorphChain, S3Gate, StorageNode
+from frostfs_testlib.storage.dataclasses.metrics import Metrics
 from frostfs_testlib.storage.dataclasses.node_base import NodeBase, ServiceClass
 from frostfs_testlib.storage.dataclasses.storage_object_info import Interfaces
 from frostfs_testlib.storage.service_registry import ServiceRegistry
-from frostfs_testlib.storage.dataclasses.metrics import Metrics
 
 
 class ClusterNode:
diff --git a/src/frostfs_testlib/storage/dataclasses/metrics.py b/src/frostfs_testlib/storage/dataclasses/metrics.py
index 81e757c..5102402 100644
--- a/src/frostfs_testlib/storage/dataclasses/metrics.py
+++ b/src/frostfs_testlib/storage/dataclasses/metrics.py
@@ -1,3 +1,5 @@
+from datetime import datetime
+
 from frostfs_testlib.hosting import Host
 from frostfs_testlib.shell.interfaces import CommandResult
 
@@ -7,11 +9,11 @@ class Metrics:
         self.storage = StorageMetrics(host, metrics_endpoint)
 
 
-
 class StorageMetrics:
     """
     Class represents storage metrics in a cluster
     """
+
     def __init__(self, host: Host, metrics_endpoint: str) -> None:
         self.host = host
         self.metrics_endpoint = metrics_endpoint
@@ -29,7 +31,7 @@ class StorageMetrics:
         additional_greps = " |grep ".join([grep_command for grep_command in greps.values()])
         result = shell.exec(f"curl -s {self.metrics_endpoint} | grep {additional_greps}")
         return result
-    
+
     def get_all_metrics(self) -> CommandResult:
         shell = self.host.get_shell()
         result = shell.exec(f"curl -s {self.metrics_endpoint}")
diff --git a/src/frostfs_testlib/storage/dataclasses/node_base.py b/src/frostfs_testlib/storage/dataclasses/node_base.py
index 8291345..d83c08e 100644
--- a/src/frostfs_testlib/storage/dataclasses/node_base.py
+++ b/src/frostfs_testlib/storage/dataclasses/node_base.py
@@ -185,9 +185,7 @@ class NodeBase(HumanReadableABC):
 
         if attribute_name not in config.attributes:
             if default_attribute_name is None:
-                raise RuntimeError(
-                    f"Service {self.name} has no {attribute_name} in config and fallback attribute isn't set either"
-                )
+                raise RuntimeError(f"Service {self.name} has no {attribute_name} in config and fallback attribute isn't set either")
 
             return config.attributes[default_attribute_name]
 
@@ -197,9 +195,7 @@ class NodeBase(HumanReadableABC):
         return self.host.get_service_config(self.name)
 
     def get_service_uptime(self, service: str) -> datetime:
-        result = self.host.get_shell().exec(
-            f"systemctl show {service} --property ActiveEnterTimestamp | cut -d '=' -f 2"
-        )
+        result = self.host.get_shell().exec(f"systemctl show {service} --property ActiveEnterTimestamp | cut -d '=' -f 2")
         start_time = parser.parse(result.stdout.strip())
         current_time = datetime.now(tz=timezone.utc)
         active_time = current_time - start_time